The impact resistance of composite Y-shaped cores sandwich structure

In this study, a series of ballistic impact tests were performed to investigate the impact resistance and failure modes of composite sandwich structure with Y-shaped cores in the experiment and finite element method (FEM). A number of impact experiments were carried out to obtain the ballistic limit velocity and failure modes of the sandwich structures. Furthermore, based on the Hashin and Yeh failure criteria, a progressive damage model was introduced into the user subroutine VUMAT to simulate the impact responses of the sandwich structure in Abaqus/Explicit. The residual velocity, ballistic limit velocity and failure modes were presented experimentally and numerically, and a good agreement was found between the numerical results and experimental results. The results shown that the front face sheet of the sandwich structures experienced shear failure at all impact tests, while the delamination and cracking were observed on the rear face sheet. The platform and flange played important roles in resisting impact loading at low impact velocity, while the vertical leg made important contributions for the impact resistance at high impact velocity as well. The ballistic limit velocity of the structure was adopted to quantitatively evaluate the anti-impact effect of sandwich structure with Y-shaped core. The ballistic limit velocity of composite sandwich structure was 133.2 m/s, while the ballistic limit velocity of the laminate was 115.3 m/s. The ballistic limit velocity of composite sandwich structure increased by 15.52% compared with that of the laminate. By comparison, it could be reasonably concluded that the impact resistance capabilities of composite sandwich structure with Y-shaped cores were superior to that of the laminate. Moreover, the effect of the impact position on the impact response was studied in the numerical simulation.